They found Gulf War illness was most prevalent in the veterans who served in Iraq or Kuwait — or the combat zones — who took pyridostigmine bromide pills, which were small doses of nerve agent meant to help troops build up a resistance in case of a chemical attack.

The researchers knew that similar poisons are found in the insect repellents Deet and Permethrin, which were used topically or sprayed on uniforms during the war, and in pyridostigmine, which soldiers took as an anti-nerve-gas pill.

The Binns report estimates that more than a quarter of the GIs deployed during Desert Storm, around 200,000 of them, are suffering in some way from Gulf War Syndrome, and identifies two primary causes: pyridostigmine bromide, an anti-nerve gas medication all troops in the Gulf were required to take, and highly concentrated, DEET-like insect-repellents that were extensively used.

The government study also concludes that 'Gulf War Illness' was primarily caused by an anti-nerve gas medication, pyridostigmine bromide, give to all troops in the Gulf Theater, and use of powerful pesticides and insect-repellents like highly concentrated DEET.